Effect of grain size on the micro-tribological behavior of pure titanium processed by high-pressure torsion

Wang, Chuan Ting; Gao, Nong; Gee, M.G.; Wood, R.J.K.; Langdon, Terence G.

doi:10.1016/j.wear.2012.01.012

Cited by 103 publications

(52 citation statements)

References 46 publications

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“…The H-P relationship for Ti; [81] grades 1 to 4 denote increasing orders of impurities for Fe, N and O and using experimental data. [81][82][83][84][85][86][87][88][89][90][91][92][93][94][95][96][97][98][99][100] Figure 4. The H-P relationship for coarse-grained and HPT processed Al-5% Mg; [103] with increasing numbers of turns, HAGBs develop and the H-P relationship is followed so that data from coarse grain samples fall on the same line as HPT specimens.…”

Section: Figure Captionsmentioning

confidence: 99%

The Strength–Grain Size Relationship in Ultrafine-Grained Metals

Balasubramanian

Langdon

2016

Metall Mater Trans A

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Metals processed by severe plastic deformation [SPD] techniques, such as equal-channel angular pressing [ECAP] and high-pressure torsion [HPT], generally have submicrometer grain sizes. Consequently, they exhibit high strength as expected on the basis of the HallPetch [H-P] relationship. Examples of this behavior are discussed using data on Ti, Al-Mg 1 and Ni. These materials typically have grain size above ~50 nm where softening is not expected. An increase in strength is usually accompanied by a decrease in ductility. High strength and ductility can be achieved simultaneously by imposing high strains to give both ultrafine grain sizes and a high fraction of high-angle grain boundaries. An example is presented for a cast Al-7% Si alloy processed by HPT. In some cases, SPD may produce a fine grain size but also lead to a weakening due to microstructural changes as in ECAP of an Al-7034 alloy and HPT of Zn-22% Al. In SPD-processed materials, grain boundary segregation and nanostructural features are present which may lead to higher strengths than those predicted by the H-P relationship in some alloys having nano grain sizes.

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Section: Figure Captionsmentioning

confidence: 99%

The Strength–Grain Size Relationship in Ultrafine-Grained Metals

Balasubramanian

Langdon

2016

Metall Mater Trans A

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“…Thus, it is generally not suitable for use in artificial joints which seek materials with high strength and good tribological properties. Recently, pure titanium with ultra-fine grain sizes, processed through the application of severe plastic deformation (SPD), appears to offer an alternative possibility for the production of implant materials [5,6]. In severe plastic deformation processing, a high level of straining is imposed on a metal using an extensive hydrostatic pressure and the strain is achieved without changing the overall dimensions of the material [7,8].…”

Section: Introductionmentioning

confidence: 99%

“…To date, various severe plastic deformation processing methods have been applied successfully for the production of high strength pure Ti [6,[14][15][16][17]. However, the evidence suggests that severe plastic deformation processing may lead to only a relatively minor improvement in the wear resistance of Ti [5,18]. As an alternative approach, it appears that surface treatments or coatings may be necessary to enhance the service durability of titanium as implant components [19].…”

Section: Introductionmentioning

confidence: 99%

Indentation and scratch testing of DLC-Zr coatings on ultrafine-grained titanium processed by high-pressure torsion

Wang

Escudeiro

Polcar

et al. 2013

Wear

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High-pressure torsion was employed to refine the microstructure of grade 2 Ti under an imposed pressure of 3.0 GPa at room temperature. The microhardness of grade 2 Ti increased from 1.82 GPa for the coarse grain state to 3.05 GPa after high-pressure torsion processing, where this value is very close to the hardness of the Ti-6Al-4V alloy.Subsequently, several diamond-like carbon (DLC) coatings with thicknesses of ~1.4 Pm were deposited on as-received Ti, high-pressure torsion processed Ti and Ti-6Al-4V samples via physical vapour deposition. Both indentation and scratch tests showed a much improved adhesion of DLC-7Zr, DLC:H-7Zr and DLC-9Zr coatings with high-pressure torsion processed Ti as the substrate by comparison with the same coatings on coarse-grained Ti. The results suggest that commercial pure Ti processed by high-pressure torsion and coated with a diamond-like carbon coating provides a potential candidate material for bio-implant applications.

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“…Grain refinement is an effective way to improve both strength and plasticity of polycrystalline metallic materials, and the improvement of strength follows a well-known Hall-Petch relationship approximately [4][5][6]. Therefore, the ultra-fine grained (UFG) metallic materials with an average grain size of 0.1-2 µm usually exhibit higher strength and ductility, compared with the coarse grained (CG) counterparts [7,8].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of an Ultra-Fine Grained Pure Titanium with High Strength and Good Ductility via ECAP plus Cold Rolling

Jiang

Liu

et al. 2017

Metals

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Microstructure evolutions and mechanical properties of a commercially pure titanium (CP-Ti, grade 2) during multi-pass rotary-die equal-channel angular pressing (RD-ECAP) and cold rolling (CR) were systematically investigated in this work, to achieve comprehensive property for faster industrial applications. The obtained results showed that the grain size of CP-Ti decreased from 80 µm of as-received stage to 500 nm and 310 nm after four passes and eight passes of ECAP, respectively. Moreover, abundant dislocations were observed in ECAP samples. After subsequent cold rolling, the grain size of ECAPed CP-Ti was further refined to 120 nm and 90 nm, suggesting a good refining effect by combination of ECAP and CR. XRD (X-ray diffractometer) analysis and TEM (transmission electron microscope) observations indicated that the dislocation density increased remarkably after subsequent CR processing. Room temperature tensile tests showed that CP-Ti after ECAP + CR exhibited the best combination of strength and ductility, with ultimate tensile strength and fracture strain reaching 920 MPa and 20%. The high strength of this deformed CP-Ti originated mainly from refined grains and high density of dislocations, while the good ductility could be attributed to the improved homogeneity of UFG (ultra-fine grained) microstructure. Thus, a high strength and ductility ultra-fine grained CP-Ti was successfully prepared via ECAP plus CR.

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Effect of grain size on the micro-tribological behavior of pure titanium processed by high-pressure torsion

Cited by 103 publications

References 46 publications

The Strength–Grain Size Relationship in Ultrafine-Grained Metals

The Strength–Grain Size Relationship in Ultrafine-Grained Metals

Indentation and scratch testing of DLC-Zr coatings on ultrafine-grained titanium processed by high-pressure torsion

Fabrication of an Ultra-Fine Grained Pure Titanium with High Strength and Good Ductility via ECAP plus Cold Rolling

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